problem
solution
codes
#include<iostream>
#include<algorithm>
using namespace std;
int N, R, x[1000];
int main(){
while(cin>>R>>N && R!=-1 && N!=-1){
for(int i = 0; i < N; i++)cin>>x[i];
sort(x, x+N);
int cur = 0, ans = 0;
while(cur < N){
int l = x[cur++];
while(cur<N && x[cur]<=l+R)cur++;
int r = x[cur-1];
while(cur<N && x[cur]<=r+R)cur++;
ans++;
}
cout<<ans<<"
";
}
return 0;
}